Do denormalization and clustering help minimize data access time for small records (by reducing joins and improving locality)?

Difficulty: Easy

Correct Answer: Valid — both can reduce access time for small rows

Explanation:


Introduction / Context:
Performance tuning often weighs normalization against practical access patterns. For small records, denormalization (fewer joins) and clustering (co-locating related rows) can reduce I/O and latency.


Given Data / Assumptions:

  • Small rows allow many tuples per page; good clustering increases hit rate.
  • Denormalization stores pre-joined attributes to avoid repeated join costs.
  • Workloads include frequent lookups or range scans on co-accessed attributes.


Concept / Approach:
Denormalization trades write complexity and redundancy for faster reads. Clustering arranges data physically to exploit locality, benefiting small-row scenarios where more rows fit into fewer pages.


Step-by-Step Solution:
Identify read-heavy queries that currently require multiple joins.Evaluate denormalization to embed frequently joined attributes.Use clustered indexes or storage ordering to keep related rows adjacent.Measure I/O reductions and latency improvements.


Verification / Alternative check:
Explain plans and buffer cache statistics typically show fewer logical and physical reads after appropriate denormalization and clustering.


Why Other Options Are Wrong:
Benefits are not limited to large rows, columnar stores, index-disabled states, or exclusively OLTP workloads.


Common Pitfalls:
Excessive denormalization causing anomalies; clustering on a column with low correlation to access patterns.


Final Answer:
Valid — both can reduce access time for small rows

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